Why didn't you just use your water pump to push antifreeze through the system, even easier. Drain and bypass your hot water tank, disconnect the suction to the pump, screw on a plastic fitting and hose, put the end in the water line antifreeze, turn on the pump and open ever faucet one at a time until you get pink stuff coming out. Don't forget the toilet and outside faucets. Drain the black and grey tanks for the water you pushed out the faucets. Make sure you put some antifreeze in the p traps/drains.
Using the Camco outside to the water fitting leaves water in the water pump because of the check valve.
I use to use air until one year the kitchen faucet and toilet valve froze and broke. When your done leave the faucets open to give room for expansion.